Butt splicer for wire fabric



Jan. 25, 1966 v. E. Hl-:NLEY ETAL 3,231,447

BUTT SPLICER FOR WIRE FABRIC Filed Aug. 6, 1962 5 Sheets-Sheet 1INVENTORS Virgil E. .Henley Martin 2V. Robertson aha7, M ,Lzzm ATTORNEYS5 Sheetscshei va E, HENLYMAL BUTT SPLIGER im @MEMBRE f2/V/Y//////////////ff Jam, 25p m66 Filed Aug. 6 1962 Jan. 25, 1966 v. E.HENLEY ETAL 3,231,447

BUTT SPLICER FOR WIRE FABRIC Filed Aug. 6, 1962 5 Sheets-Sheet 3 Martin.lV-Roberifson 7% @Mw mb ATTORNEYS Jam., 25, 1966 v. E. HENLEY ETAL3,231,447

BUTT SPLICER FOR WIRE FABRIC Filed Aug. 6, 1962 CWNK 5 Sheets-Sheet 4Fig l mvENToRs Vir-gil E.Heney Marlin MHobertson ATTORNEYS Jan. 25, 1966v. E. HENLEY ETAL 3,23,447

BUTT SPLICER FOR WIRE FABRIC 5 Sheets-Sheet 5 Filed Aug. 6, 1962 S www nOZB N Tnb R we@ m WHRM IEN n J United States Patent 3,231,447 BUTTSPLICER FR WIRE FABRIC Virgil E. Henley and Martin N. Robertson, Akron,Ghia, assignors to rEhe General Tire t Rubber Company, Akron, Unio, acorporation of hio Fiied Aug. 6, i962, Ser. No. 215,108 Claims. (Cl.156-502) This invention relates to a machine for butt splicingreinforced tire carcass fabric or other sheet material.

The machine of the present invention is designed primarily for buttsplicing sheet material such as rubbercoated tire fabric and providesmeans for tightly gripping the end portions of the material adjacent theline of splice and squeezing the end edges together while tightlygripped with suiiicient pressure to integrally join the sheet materialalong the splice line. It has been found desirable in the manufacture ofrubber articles such as tires which are formed of superposed plies inthe form of rubber sheets having parallel textile cords or metal wiresembedded therein to splice the sheet material edge to edge Withoutoverlapping the sheets. By so splicing the sheet material prior tocuring, more even cross section in the finished product is provided.

The machine of the present invention is particularly adapted for thebutt splicing of wire reinforced ply stock. In the machine herein shown,the wire cords run perpendicular to the length of the ply. Generally,each tire ply is made up of two or more sheets cut along paralleltransverse lines from a calendered lstrip in which closely spaced cordsparallel to the longitudinal edges of the strip are embedded. These cutsheets are then spliced along .the edges which are parallel to thecords. The resulting ply is then used in the manufacture of tires inwhich the cords run parallel to the tire axis. It is thereforeparticularly important to have strong splices since the stretching ofthe plies when the uncured tire is expanded into a vulcanizing moldsubjects the rubber to tensile stresses which could cause separations ofthe mateiial along splice lines unless a strong union is provided ateach spl-ice.

The present machine utilizes an aligning means for accurate positioningof the material and applies high pressures to the abutting ends of thesheet material to insure proper adhesion of the rubber. The completedsplice has no appreciable excess of extruded rubber along the line ofspl-ice and resists tearing equally as well as unspliced sections of theply.

It is an object of the present invention to provide a machine for buttsplicing the ends of unvulcanized cord y reinforced rubber tire carcassmaterial which makes a splice generally as strong as the unsplicedportions.

It is a further object of the present invention to provide an accuratemeans of aligning sheet material edges along a desired line of splicewithout resort to the visual judgment of the machine operator.

It is a further object of the present invention to provide a machinewhich makes a splice of uniform strength throughout the thickness andwidth of the material.

Referring to the drawings,

FIGURE l is a side elevation of a machine embodying the invention.

FIGURE 2 is a front sectional view of the same machine taken on the line2-2 of FIGURE 1 and of the same scale.

FIGURE 3 is a top plan view of the same machine with parts broken awayshowing the working parts of the lower platen assembly and taken on aline 3 3 of FIGURE l.

FIGURE 4 is a fragmentary longitudinal sectional view on a larger scaletaken on the line 4 4 of FIGURE 3.

FIGURE 5 is a fragmentary top sectional view taken on the line 5-5 ofFIGURE 4.

FIGURE 6 is a continuation of the longitudinal sectional view of FIGURE4 taken on the line 6-6 of FIGURE 3.

FIGURE 7 is a fragmentary top elevation of the same machine with partsbroken away and showing the jaws in their outward or open position.

FIGURE 8 is another fragmentary top elevation with parts broken awayshowing the jaws in their inward or closed position.

FIGURE 9 is a transverse sectional View of the lower platen assemblytaken on the line 9--9 of FIGURE 7.

FIGURE 10 is a transverse sectional view of the lower platen assemblytaken on the line 10-10 of FIGURE 8.

FIGURE 11 is a fragmentary longitudinal sectional view of the ysamemachine taken on the centerline thereof.

FIGURE 12 is a fragmentary transverse sectional View of the lower platenassembly taken on the line 12-12 of FIGURE 4, showing the positioningblade in its raised pOs1t1on.

FIGURE 13 is a fragmentary transverse sectional view of the same machinetaken on the line 13-13 of FIG- URE 11.

FIGURE 14 is a fragmentary transverse sectional view of the same machinetaken on the line 14-14 of FIG- URE 1l and showing on a larger scale thesplicing jaws engaging the material prior to their inward movement.

FIGURE 15 is a fragmentary transverse sectional view of the same machinetaken on the line 14-14 of FIG- URE 11 and showing on a larger scale thesplicing jaws engaging the material and pressing the butt ends together.

FIGURE 16 shows a section of material having been spliced by the machinealong the line X-X.

FIGURE 17 is a top plan view of the lower platen assembly of a modifiedform of the machine embodied in the invention.

FIGUREIS is a fragmentary top elevation of the same machine with partsbroken away.

FIGURE 19 is a fragmentary transverse sectional view of the lower platenof the same machine taken on the line 19-19 of FIGURE 184 andof the samescale.

FIGURE 20 is av fragmentary side elevation of the same machine showingthe upper platen assembly in both its raised and lowered positions.

FIGURE 21 is a fragmentary end elevation of the same machine showing theupper platen in both its raised and lowered positions corresponding tothose shown in FIGURE 20. j

Referring more particularly to the drawings, FIG- URES lthrough 1-5 showa machine embodying the invention for bu-tt splicing wire reinforcedtire carcass fabric in lwhich the cords run perpendicular to the lengthof the ply. FIGURE 1 shows a frame A which supports the working parts, alower platen assembly B which supports the end portions of material tobe spliced, a vertically movable upper platen assemblyC and a pneumaticair cylinder D. The air cylinder D supports the upper platen assembly Cand provides pressure for moving it up and down. When compressed air isforced into the cylinder at the top 1, the piston 2 is forced downwardto lower the upper platen assembly to its lower position shown in dashedlines in FIG. l where it compressively engages the material to bespliced. When air is forced into the bottom of the cylinder 3, thepiston is driven upward to lift the lower platen assembly t-o itsuppermost position.

Longitudinal stability of the upper platen assembly is provided for bylongitudinally spaced vertical guide racks 4 which move up and down withthe platen assembly. The racks 4 engage spur gears 5 mounted on the sameshaft 6. The shaft is mounted in housings 7 in the frame A.

Lateral stability of the upper platen is provided during verticalmovement by guide rollers i shown in FIGURE 1 and 2, which engage fixedvertical tracks 9 located in the frame.

FIGURE 3 shows the operating mechanism of the lower platen assembly B.The operating mechanism of the upper platen assembly is substantiallyidentical to that of the lower platen assembly and is not shown indetail. The assembly B includes two relatively movable splicing jawswhich have opposed longitudinal edges adapted to engage. As hereinshown, each jaw is mounted to move toward and away from the other. Thejaws 10 are moved by a series of toggle links 11 connected to the jawsby pivot pins 12 at equally spaced points along the length thereof. Theopposite end of each link is connected by a pivot pin 13 to a movablepush bar 14 which moves in a direction parallel to the jaws. There arefour such push bars 14 two of wh-ich are part of the lower platenassembly and two of which are part of the upper platen assembly.

The push bars 14 in the lower platen assembly are locked together forsimultaneous longitudinal movement by a cross bar 15. A piston 16extending from an air cylinder 17 is attached to the cross bar 15 foractivating the push bars 14 to move the jaws 1li. Movement of the piston16 is controlled by a solenoid activated valve 18 which `controls theentry of compressed air into the cylinder 17. The solenoid operating thevalve 1S may be controlled manually but is preferably automaticallycontrolled through a suitable timer (not shown) that may be energized bythe upper platen as it approaches its lowermost position to actuate thetwo pairs o-f jaws after the full gripping pressure is applied to thesheet material.

Each push bar 14 in the lower platen assembly has a rack 19 attachedthereto and movable therewith and each of these racks engages a spurgear Ztl on a vertical splined shaft 21 as shown in FIGURES 1, 2 and 3.Both of the splined shafts 21 extend vertically upward through the upperplaten assembly C and each shaft 21 is rotatably mounted in a bearing 22in the upper lframe. A second spur gear 23 is keyed on each shaft 21 andis slaved to move up and down with the upper platen assembly. Each ofthese upper platen spur gears 23 engages a rack on an upper platen pushbar 14. This gearing means locks the jaw movement of the upper platenassembly to the jaw movement of the lower platen assembly and providesfor a coordinated synchronized movement thereof.

FIGURES 7 and 8 show the operation of the jaws in the lower platenassembly in greater detail. FIGURE 7 shows the jaws 1t) in their outwardor open position leaving a gap along a center-line 24. The position ofthe jaws at this point in the cycle may be adjusted for variations inmaterial gage.

The movement of the jaws is guided by guide pins 25 in each jaw whichmove in slots 26 in the lower platen assembly base plate 27. The jawsare supported on antifriction thrust bearings 2,8 carried by the baseplate 27. The thrust bearings may be of any standard variety, thebearings 2S herein shown having ball bearings held in circular tracks.The guide pins 25 extend downwardly from the jaws lltl through thecenter of the thrust bearings 23 and into slots 26 of the base plate 27.

As the push bars 14 are moved toward the front of the platen assembly,the links 11 move from a diagonal position in relation to the push barsto a position perpendicular thereto as shown in FIGURE 8. The movementof the links 11 moves the jaws lll toward a centerline 24 where they maycome into contact. The mechanical advantage provided by the linkassembly increases as the link approaches the perpendicular position.The total distance moved by the push bars is quite small. In the machineillustrated herein, the push bars have a movement of S while the totalmovement of each jaw is 3/32. It is desirable that the movement of theindividual Biffi/17 jaws be slight in order to provide an advantageousmultiplication of thrust throughout the pressure applying operation.

Movement of the push bars 1d is facilitated by antifriction bearingssuch. as rollers 29 carried by the push bars. The rollers 29 bearagainst side plates 3) of the platen assemblies. Movement of the jaws totheir separated position is aided by springs 31 which bear against acenter bar 32 attached to the base plate 27 and parallel to the jaws 1band against jaw mounting bars 33, one forming part of each jaw 10 asshown in section in FIGURES 9 `and 10. The springs 31 are located atintervals along the jaws and provide for free and uniform movement.

The splicing cycle is begun by aligning the end edges `of the sheetmaterial to be spliced along the longitudinal centerline 24 of the lowerplaten assembly B with the upper surface of each lower jaw pressureplate 34 engaging the bottom surface of one end portion of the sheetmaterial. The upper platen assembly C is then lowered to a positionwherein the lower surface of each upper jaw pressure plate 35 engagesthe top surface of one end portion of the sheet material. The jaws inthe upper platen assembly C are mounted in a manner substantiallyidentical to that of the jaws in the lower platen assembly to providetwo pairs of vertically opposed jaws for gripping each end portion ofthe sheet material. The gripping .pressure is sufficient to preventslipping of the sheet material relative to the jaws. The sequence ofmovements of the machine is timed to provide rm engagement of the sheetmaterial by the gripping jaws before the gripping jaws are movedtogether. With the eind portions of the sheet material tightly gripped,the gripping pairs of jaws are moved toward each other to press the endedges of the material together with sucient force to make a splice. Theupper platen assembly C is then raised while its jaws are still in theirinnermost position and the spliced material removed from the machine.

Positioning of the material for splicing may be facilitated by a thindepressable aligning blade 36 which in its elevated position extendsabove the upper surface of the lower platen assembly B between andparallel to the opposed edges of the lower gripping jaw. The blade 3aprovides a guide against which the end edges of the pieces of sheetmaterial to be spliced may be positioned.

The blade 36 is carried in a carrier bar 37 located below the jaws. Whenthe blade is depressed, it retracts below the upper surface of the lowerplaten assembly to permit the jaws to move inward until they meet.

Depression of the blade is accomplished by two pins 38 in the upperplaten C positioned to straddle the material to be spliced, which, whenthe upper platen assembly is lowered, engage the blade carrier bar 37and depress it to a position below the top surface of the platen asshown in FIGURES 13, 14 and 15. The blade carrier bar 3'7 has verticalrods 39 attached thereto adjacent its opposite ends and these rods areslidably mounted in threaded bushings 4i) that are screwed into verticalthreaded openings in the base plate 27.

The blade 36 is biased toward its upper position by means of springs 41interposed between the blade carrier bar 37 and the bushings dil. Byadjusting the bushings in the base plate 27 the tension of the springs41 may be varied. Below the bushings the rods 39 have transverse notchesft2 with which a horizontally movable locking plate 43 may be engaged tolock the carrier bar 37 in its lowered position. The locking plate 43extends parallel to the carrier bar 37 beneath the base plate 27 and haselongated slots 44 through which the rods 39 extend. The plate 43 issupported and guided for longitudinal movement in brackets i5 suspendedfrom the base plate 27. At one end thereof the locking plate 43 has a Tshaped handle lvl-6 which forms an extension thereof and which isslidably mounted in plate 47 which forms the front side of the frame A.A spring 48 presses the plate 43 toward the rear of the frame A andnormally holds the front ends of the slots 44 in engagement with therods 39. When the carrier bar 37 is in its uppermost position, the rods39 are engaged by the plate 43 below the notches 42; and when the bar 37is depressed, the plate 43 is moved into locking engagement with thenotches 42 to hold the carrier bar 37 and in a position where the blade36 is below and clear of the opposed edge portions of the jaws 10. Bypulling on the handle 46, the rods 39 may be released to permit thecarrier bar 37 and positioning blade 36 to be raised by the springs 41.v The locking means retains the positioning blade in its loweredposition after the upper platen C is raised and permits spliced materialto be removed from the machine without interference from the blade.After removal of the spliced material, the blade may be manuallyreleased and moved by the springs 41 to its uppermost position prior tothe next splicing operation.

` FIGURES 1l, 14 and 15 show the upper platen assembly C in itslowermost position where the pins 38 have depressed the blade 36 and thejaw pressure plates 34' and 35 are in gripping engagement with the endportions of the pieces of sheet material.

FIGURE 14 shows the jaw pressure plates in gripping engagement with thepieces of sheet material prior to the inward movement of the jaws. Theend portions of the pieces of ysheet material extend slightly inwardpast the edges of the jaw pressure plates 34 and 35. The gripping jaws'when moved inwardly cause pressure to be exerted against the edges ofthe sheet material to integrally join said edges. During the inwardmovement of the'pairs of gripping jaws, the upper platen jaw pressureplates 35 press downward against the material with sufcient force toprevent slippage of the sheet material due to endwise pressure. Thepressure maintained on the sheet material by the pressure plates 35 isat least 25 p.s.i. for wire cord fabric. The gripping surfaces of theupper platen jaw face plates 35 may be slightly slanted downward towardthe centerline 24 as shown in FIGURE 13 to provide higher pressure nearthe splice line and to allow for some springing of the jaws when fullpressure is applied.

FIGURE 15 shows the parts at the completion of the splicing movement.The edges of the jaw pressure plates meet along the centerline, and theedges of the material are forcefully pressed against each other. Therubber is extruded slightly into slots 49 and 50 formed by the bevelededges of the jaw pressure plates. It is preferable that the applicationof vertical pressure be controlled to reach a maximum amount after thejaws have been brought together.

The rigid center bar 32 in the lower platen assembly comprises twoidentical parts on either side of the centerline 24 which engages thebottom faces of the lower jaw pressure plates 34 to prevent springing ofthese plates. An upper platen center bar 51 receives the thrust of thepiston 1 and applies pressure to the upper platen jaw pressure plates35.

FIGURE 16 shows a portion of the sheet material which has been splicedalong the line X-X.

FIGURES 17-20 show a modified form of a machine embodying the inventiondiffering mainly in the means used to activate the push bars 52 and forsynchronizing the movement thereof. In FIGURES 17-21, parts which areidentical with parts previously described are designated by the samereference numerals. In this modification, the pairs of gripping jaws areactivated to press the edges of the sheet material together by means ofa manually operated mechanism. The lower platen push bars 52 are lockedtogether by a cross bar 53 which has a threaded hole 54 in its center asshown. A screw 55 with a T handle 56 is rotatably mounted on the lowerplaten assembly E as shown and engages the threads in the hole 54. Whenthe screw 55 is turned counterclockwise, the lower platen push bars 52are moved toward the front of the machine to operate the jaws in themanner previously described.

The lower platen push bars have a member 57 slotted to provide atransverse channel which receives a cross bar 58 connecting the upperplaten push bars 52 when the upper platen assembly is lowered to engagethe material. When the upper platen assembly is lowered to engage thesheet material, the cross bar 58 of the upper platen push bars 52 islocked to the member 57 connecting the lower platen push bars 52 toprovide synchronized movement of all the jaws.

Another distinguishing feature of this embodiment of the invention isthe location of the roller bearings 59 for receiving side thrust fromthe push bars 52. Here the rollers 59 are mounted in the side plates 60of the platen assemblies E and F as shown in FIGURES 18 and 19.

It has been found preferable to provide the jaw pressure plates in theabove described machines with a slight convex longitudinal bow, forexample, to provide a low of .O25 inch in a length of 40 inches. Thiscompensates for flexing which may occur in the upper platen when fullvertical pressure is applied.

The rollers which bear side thrust from the push bars are preferablylocated near the pivot pins on the push bars to which the links areattached. This provides for more direct transmission of side thrust tothe platen assembly side plates.

It is preferable that a high vertical pressure be applied to the endportions of the material which are gripped by the jaws. Wire cord fabricdoes not permit much extrusion and, therefore, high pressing forces willnot normally cause substantial thinning of the material. It is essentialthat the vertical pressure provide a frictional resistance to slippagebetween the jaws and the sheet material which will exceed the horizontalforce against the edges of the rubber during splicing.

It is also preferable that there be a time delay While the jaws are intheir inward position for splicing. This permits more extrusion of therubber and allows the rubber to absorb more of the heat generated by thepressure to provide more intermolecular adhesion.

It will be understood that the above description is by way ofillustration rather than limitation and that, in accordance with theprovisions of the patent laws, variations and modifications of thespecic machines herein shown and described may be made without departingfrom the spirit of the invention.

Having described our invention, we claim:

1. A machine for butt splicing sheet material comprising a lower platenassembly for sustaining vertical force and for supporting two endportions of sheet material with their end edges parallel and closelyspaced for splicing along a transverse splice line, said lower platenassembly having two lower jaws, one on each side of said transverse lineand mounted for relative movement one toward or away from the other, anupper platen assembly located above said lower platen assembly andmounted for vertical movement, said upper platen assembly having twoupper jaws facing the lower platen assembly to provide with said lowerjaws two pairs of jaws for gripping the pieces of sheet materialadjacent their closely spaced ends, a depressible spring-loaded bladeassembly for positioning two end portions of sheet material forsplicing, said assembly including a relatively thin blade verticallypositioned along said splice line, said blade protruding above andperpendicular to the surface of said lower platen assembly when in itsraised position, means biasing said blade to its rais-ed position, meanslocated in said upper platen assembly for contacting said blade assemblywhen said upper platen assembly is lowered and for pushing said bladeassembly down to a depressed position below the surface of said lowerplaten, and a releasable locking assembly to hold said blade assembly inits depressed position when said upper platen assembly is raised, meansfor raising and lowering said upper platen assembly and means for movingthe gripping pairs of paws one toward the other while in grippingengagement with said sheet material to press the end edges of said sheetmaterial together to splice them.

2. A machine for butt splicing sheet material comprising a frame, alower platen assembly for sustaining vertical force and for supportingtwo end portions of sheet material with their end edges parallel andclosely spaced for splicing along a transverse line between said edges,said lower platen assembly having two movable lower jaws, one on eachside of said transverse line and slidably mounted in said lower platento move inwardly and outwardly toward and away from said transverseline, on upper platen assembly located above said lower platen assemblyand mounted for vertical movement, said upper platen assembly having twomovable upper jaws facing the lower platen assembly to provide with saidlower jaws two pairs of jaws for gripping the pieces of sheet materialadjacent their closely spaced ends, a relatively thin blade verticallypositioned along said transverse line extending above and perpendicularto the upper surface of said lower platen assembly for positioning twoend portions of sheet material with their end edges parallel and closelyspaced for splicing along said transverse line, means for depressingsaid blade below the upper surface of said lower platen and for holdingthe same in depressed position, means for raising and lowering saidupper platen assembly and for causing said jaws to grip the sheetmaterial, and means for moving the gripping pairs ofv jaws one towardthe other while held in gripping engagement with said sheet material topress the end edges of said sheet material together to splice them.

3. A machine as defined in claim 2 wherein the means for depressing saidblade below the upper surface of said lower platen assembly comprisesrigid projections carried by the upper platen extending below the lowersurface of said upper platen assembly at points sufficiently spacedapart to straddle the material to be spliced to contact the blade whenthe upper platen is lowered and to depress the blade below the uppersurface of said lower platen assembly.

d. A machine as defined in claim 2 'wherein the means for moving thegripping jaws toward and away from the transverse splice line while ingripping engagement comprises movable push bars, each interconnected byhorizontally movable links to one of said jaws, said bars being mountedfor longitudinal motion substantially perpendicular to the direction ofmotion of said jaws and said links being each pivotally connected at onepoint to a movable push bar and at another point to one of said jaws tomove the jaws toward and away from said transverse line when said pushbar is moved through its range of longitudinal motion, rollers attachedto each push bar which bear against said platen assemblies to transmithorizontal thrust and to facilitate the movement of said push bars,gearing means for moving all of said push bars simultaneously anduniformly to move alll of said jaws inwardly and outwardly with acoordinated, synchronized motion, a pneumatic air cylinder to operatesaid bars, and a control means for said pneumatic air'cylinder.

5. A machine as defined in claim 4 wherein the gearing means for movingall of said push bars simultaneously and uniformly comprises a rack oneach push bar of said lower platen assembly, a lower spur gear 'mountedon and rotatable with a vertically positioned splined shaft meshing witheach of said racks, an upper spur gear slidably mounted on each of saidsplined shafts, said upper spur gears being slave mounted for verticalmovement on said splined shaft with said upper platen assembly, andbeingl keyed in said splined shaft to rotate with said shaft, a rack oneach push bar in said upper platen assembly, each of said racks beingmounted for engagement with one of said spur gears mounted to move withsaid upper platen to move said push bars simultaneously.

References Cited by the Examiner UNlTED STATES PATENTS 3,100,731 8/1962Brey 15G-502 3,075,571 1/1963 Wise 156-502 EARL M. BERGERT, PrimaryExaminer.

DOUGLAS I. DRUMMOND, Examiner.

1. A MACHINE FOR BUTT SPLICING SHEET MATERIAL COMPRISING A LOWER PLATENASSEMBLY FOR SUSTAINING VERTICAL FORCE AND FOR SUPPORTING TWO ENDPORTIONS OF SHEET MATERIAL WITH THEIR END EDGES PARALLED AND CLOSELYSPACED FOR SPLICING ALONG A TRANSVERSE SPLICE LINE, SAID LOWER PLATENASSEBMLY HAVING TWO LOWER JAWS, ONE ON EACH SIDE OF SAID TRANSVERSE LINEAND MOUNTED FOR RELATIVE MOVEMENT ONE TOWARD OR AWAY FROM THE OTHER, ANUPPER PLATEN ASSEMBLY LOCATED ABOVE SAID LOWER PLATEN ASSEMBLY ANDMOUNTED FOR VERTICAL MOVEMENT, SAID UPPER PLATEN ASSEMBLY HAVING TWOUPPER JAWS FACING THE LOWER PLATEN ASSEMBLY TO PROVIDE WITH SAID LOWERJAWS TWO PAIRS OF JAWS FOR GRIPPING THE PIECES OF SHEET MATERIALADJACENT THEIR CLOSELY SPACED ENDS, A DEPRESSIBLE SPRING-LOADED BLADEASSEMBLY FOR POSITIONING TWO END PORTIONS OF SHEET MATERIAL FORSPLICING, SID ASSEMBLY INCLUDING A RELATIVELY THIN BLADE VERTICALLYPOSITIONED ALONG SAID SPLICE LINE, SAID BLADE PROTRUCING ABOVE ANDPERPENDICULAR TO THE SURFACE OF SAID LOWER PLATEN ASSEMBLY WHEN IN ITSRAISED POSITION, MEANS BIASING SAID BLADE TO ITS RAISED POSITION, MEANSLOCATED IN SAID UPPER PLATEN ASSEMBLY FOR CONTACTING SAID BLADE ASSEMBLYWHEN SAID UPPER PLATEN ASSEMBLY IS LOWERED AND FOR PUSHING SAID BLADEASSEMBLY DOWN TO A DEPRESSED POSITION BELOW THE SURFACE OF SAID LOWERPLATEN, AND A RELEASABLE LOCKING ASSEMBLY TO HOLD SAID BLADE ASSEMBLY INITS DEPRESSED POISTION WHEN SAID UPPER PLATEN ASSEMBLY IS RAISED, MEANSFOR RAISING AND LOWERING SAID UPPER PLATEN ASSEMBLY AND MEANS FOR MOVINGTHE GRIPPING PAIRS OF PAWS ONE TOWARD THE OTHER WHILE IN GRIPPINGENGAGEMENT WITH SAID SHEET MATERIAL TO PRESS THE END EDGES OF SAID SHEETMATERIAL TOBETHER TO SPLICE THEM.